Current mobile communication service technology can be classified into asynchronous service, which is based in Europe, and synchronous service, which is based on North America. Furthermore, International Mobile Telecommunications (IMT)-2000 service, which is a new mobile communication technology standard for transferring packets at high speed, is being developed separately for use in North America and in Europe.
Synchronous IMT-2000 service (a synchronous mobile communication network) is being developed in the form of Code Division Multiple Access (CDMA) 2000 1x service, and CDMA2000 1x Evolution Data Optimized (EV-DO) EV-DO service, and Asynchronous IMT-2000 service (an asynchronous mobile communication network) is being developed in the form of Wideband Code Division Multiple Access (WCDMA) Universal Mobile Telecommunications System (UMTS) service. In these environments, the problem of roaming between a synchronous network and an asynchronous network becomes the greatest issue and, accordingly, a dual band/dual mode terminal has been developed so as to enable uninterrupted roaming between the synchronous mobile communication network and the asynchronous mobile communication network.
The asynchronous mobile communication network is being constructed for regions having great demand for service and, therefore, the synchronous mobile communication network is evolving such that the service area thereof includes the service areas of an asynchronous network. In such a process, handover between the networks is necessary to provide continuous service in the case where a user moves between the asynchronous mobile communication system and the synchronous mobile communication system.
Currently, both synchronous and asynchronous wireless devices, which are provided in a dual band/dual mode mobile communication terminal, are activated when handover is performed between the asynchronous mobile communication system and the synchronous mobile communication system. Thereafter, when the mobile communication terminal moves to the synchronous mobile communication network while communicating via the asynchronous mobile communication network, a signal from the synchronous mobile communication network is detected using the synchronous wireless device and handover is performed.
As a result, problems occur in that when only one wireless device is activated, a signal from the other type of mobile communication network is not detected, and therefore the success rate of handover is reduced. When the mobile communication terminal operates in the state in which the different wireless devices have been activated for the handover, power is excessively consumed, and therefore the lifespan of the battery is shortened.